The project objectives are to learn more of the role of androgen in ovarian physiology and to understand how polypeptide hormones might increase the quantity of their own receptor binding sites. Studies with intra-ovarian implants of the antiandrogen Flutamide or its active hydroxylated metabolite indicate that the compounds did not alter significantly progesterone or estrogen concentrations in porcine follicular fluid. The presence of intraovarian antiandrogen for 6 days in the rat appears to increase the capability of granulosa cells harvested from such ovaries to secrete progesterone in culture. Studies in vitro with moderately differentiated porcine granulosa cells indicate that various hormonal supplements to the media, individually or as combinations (insulin, cortisol, thyroxine, follicle stimulating hormone), for two or four days of culture are not able to maintain the initial level of 125I-hCG binding. Future studies will be directed toward studies of the effect(s) of antiandrogen upon luteal function in the rat and toward establishing procedures and/or conditions in vitro which will maintain or increase the number of granulosa cell LH/hCG receptors under culture conditions.